Autopilot Install Causing VHF Interference

[JLR]

I had a new pilot installed. Now, I am getting interference on my VHF even when the pilot pump itself is not running. I am going to run a shielded power cable from the VHF directly to the battery to try to eliminate the interference. In the past, I have tried ferrite beads, chokes and noise filters on other vhf’s without success. Any suggestions? The interference is enough to stop effective scanning on the VHF. Moving the pilot display (LED) or the antenna is not an option. Anything out there that is effective and not snake oil? Thanks.

 

[Boatsb]

Sometimes the installer does things that cause other systems to fail. Have him look over the installation before you start looking for fixes. It may not be the power cable.

Is the autopilot hooked up to the 24 volt power or the 12 volt?

Is the radio on a separate source?

Look at the antenna cable and have them test it too

 

[Cricket]

John, did you add anything else? We chased an VHF interference for a few years before figuring it out, had a small LED light mounted over our bridge breaker panel that the issue, before figuring that out we tried adding all the same stuff you have.

 

[JLR]

No. The autopilot has three components. The compass, the pump and the control head. The compass plugs into the control head as does the wiring from the NMEA 0183 connections. The pump gets AC power as well. So, I have shielded wire on order and broke down and bought a mix 61 set of ferrite beads. Still trying to figure out whether the interference is coming on the DC side or the antenna cable. I plan to do some looking today and will report back. I thought the most obvious source could have been the pump but the interference happens at the dock when the pump is not working. I am hoping it is not coming from the lighting in the control head which is just about two feet from the base of the antenna. That would be a real problem.

 

[racclarkson@gmail.com]

Any chance you have low dc voltage? VHF transmit is the first to go.

 

[JLR]

It is possible but the interference is on the receive side.